Cartridge chamber seal for automatic firearms with revolver drum



Allg- 1957 F. HERLACH EI'AL 2,801,573

CARTRIDGE CHAMBER SEAL. FOR AUTOMATIC FIREARMS WITH REVOLVER DRUM v Filed March 22, 1951 I 2 g- D 61/10 9 INVENTORS:

FHcr/ach E Linder a I 5 ,9 I8 4 ATTOIL N E $5 CARTRIDGE CHAMBER SEAL FOR AUTOMATIC FIREARMS WITH REVOLVER DRUM Fritz Herlach and Friedrich Linder, Zurich, Switzerland,

assignors to Machine Tools Works Oerlikon, Administration Company, Zurich-Oerlikon, Switzerland, a company of Switzerland Application March 22, 1951, Serial No. 216,882

3 Claims. (Cl. 89-13) In automatic guns with a revolver drum the cartridge chamber in which a cartridge is just being fired must be tightly connected with the front face of the barrel to avoid escape of gases during pressure development. For this purpose it is known to use bushings which are inserted into a recess in the front part of the cartridge chambers and are pressed tightly against the face of the barrel by the gas pressure. Experience shows, however, that whereas this type of bushing seals sulficiently at the face of the barrel, gases can escape from the rear along the outer wall of the bushing.

The present invention eliminates this disadvantage in that in a cylindrical recess at the front end of each cartridge chamber a seal consisting of several parts is arranged whereby the rearmost part which acts as a piston is fitted with conical faces resting against the adjacent part and radially expanding the latter during the action of the gas pressure so that it is pressed tightly against the wall of the recess.

The enclosed drawing shows two constructional examples f the subject of the present invention. In the drawing:

Fig. 1 is a diagrammatic longitudinal section of the s Fig. 2 is an enlarged section through the front part of the cartridge chamber of the first constructional example;

Fig. 3 is an enlarged section through the front part of the cartridge chamber of a second example.

As shown in Fig. l the barrel 1 is fastened by means of a bayonet to the casing 2 inside which the drum 3 is rotatably arranged. The drum 3 is fitted with a number of cartridge chambers which, on rotation of the drum 3, are successively moved in front of the barrel 1. Rotation of the drum 3 is effected in known manner by a slide 4 acting on the drum by means of curved grooves engaging the rollers 5. The slide 4 is operated by the gas piston 6 arranged in the gas cylinder '7. The cartridge feed star Wheel 9 is mounted coaxially with the drum 3 and connected to the latter by the coupling 8. From the star wheel 9 the cartridges are moved, also in known manner, in two stages into the cartridge chambers of the drum 3 by the lugs 10, 11 of the slide 4.

As shown in Fig. 2 the front part of the cartridge chambers 12 of the drum 3 is fitted with cylindrical recesses 13 containing the bushings 14, 15. The bushing 14 is inserted with its cylindrical front part into the thin-walled rear part of the bushings 15. Its conical face 16 rests against a correspondent face of the bushing 15. The front end of the bushing has a flat sealing surface 21 adapted to engage the rear end of the barrel 1. A chamfered surface 21 is located between the cylindrical outer surface of bushing 15 and the surface 21, so that when the drum 3 is rotated, the bushings 15 will be able to ride over unevenesses in the surface 23 of the casing 2. Between the rear wall 17 of the bushing 14 and the front face of the recess 13 there is a gap. During the action of the gas pressure the bushing 14 is pressed forward glue to the pressure acting upon its rear wall 17, thereby "ice the bushing 15 is pressed against the front face of the barrel. Simultaneously the rear part of the bushing 15 is pressed against the wall of the recess 13 due to the action of the radial force components caused by the conical face 16 thus forming a completely gastight connection'between cartridge chamber and barrel.

In the example shown in Fig.3 the bushing 14 rests with its conical face against a ring 18 which is supported by the conical face 20 of the front bushing 19. The gas pressure acting upon the wall 17 of the bushing 14 is transmitted to the front bushing 19 via the ring 18 whereby the ring 18 is pressed tightly against the wall of the recess 13'by the radial force components caused by the conical faces 16 and 20. The transition from the cylindrical outer surface of the bushing 19 to the flat sealing surface 21 is provided by a chamfered surface 22 in a manner similar to that shown in Figure 2.

We claim:

1. In an automatic firearm, a casing having an inner surface, a barrel located in said casing and having a rear end flush with said inner surface, a drum rotatably mounted in said casing and having formed therein a plurality of elongated cartridge chambers extending parallel to the axis of rotation of said drum, and cylindrical recesses in said cartridge chambers, the front end of said cylindrical recesses being located opposite said inner surface, sealing means consisting of a plurality of alined bushings located in each cylindrical recess and longitudinally movable therein, said bushings having formed therein a passage for the projectile element of a cartridge, said bushings further having interengaging conical surfaces, at least one of said bushings having a cylindrical sealing surface engaging the cylindrical surface of said cylindrical recess, said cylindrical sealing surface being elastically extended when said conical surfaces are shifted upon each other, the front one of said bushings further having at its front end a further sealing surface adapted to engage said inner surface of the casing, the rear one of said bushings having the form of a piston, whereby gases produced during the firing of a cartridge press said sealing surfaces against said inner surface of the casing and against the cylindrical surfaces of the cylindrical recesses.

2. In an automatic firearm, a casing having an inner surface, a barrel located in said casing and having a rear end flush with said inner surface, a drum rotatably mounted in said casing and having formed therein a plu rality of elongated cartridge chambers extending parallel to the axis of rotation of said drum, and cylindrical recesses in said cartridge chambers, the front end of said cylindrical recesses being located opposite said inner surface, two annular bushings located one behind the other in each cylindrical recess and longitudinally movable therein, said bushings having formed therein a passage for the projectile element of a cartridge, the front bushing having at its front end a flat sealing surface adapted to engage said inner surface of the casing, the rear portion of the front bushing being elastic radially and having the form of a sleeve-like element constituting a cylindrical sealing surface, said rear portion having an inner conical end surface, the rear bushing having a front portion adapted to fit into the sleeve-like element of the front bushing and a conical surface adapted to engage the conical surface of the front bushing, the rear bushing having the form of a piston actuated by gases produced during the firing of a cartridge, whereby movement of the rear bushing against the front bushing causes pressure of said cylindrical sealing surface against the cylindrical surface of said recess, as well pressure of said flat sealing surface against the inner surface of the casing.

3. In an automatic firearm, a casing having an inner surface, a barrel located in said casing and having a rear end flush with said inner surface, a drum rotatably mounted in said casing and having formed therein a plurality of elongated cartridge chambers extending parallel to the axis of rotation of said drum, and cylindrical recesses in said cartridge chambers, the front end of said cylindrical recesses being located opposite said inner surface, two annular bushings located one behind the other in each cylindrical recess and longitudinally movable therein, said bushings having formed therein a passage for the projectile element of a cartridge, said two bushings having adjacent conical surfaces extending in opposite directions, the front bushing having at its front end a fiat sealing surface adapted to engage said inner surface of the casing, the rear bushing having the form of a piston, and a ring which is elastically yieldable in References Cited in the tile of this patent UNITED STATES PATENTS 325,878 Tyler Sept. 8, 1885 466,320 Benet Jan. 5, 1892 1,965,637 Frederich July 10, 1934 

